1. Field of the Invention
This invention relates to a gas burner and a warming apparatus (i.e. a warmer) having the burner for use in agriculture and stockbreeding, and more particularly to a burner having no tendency to exhibit backfiring and a warming apparatus for use in agriculture and stockbreeding which warms agricultural products, domestic animals or poultry by radiation heat radiated by heating radiation surfaces with the gas burner.
Illustrations of suitable use of the apparatus of this invention are brooders, poult cages, swine cages, dryers for tobacco and grains, and the like.
The present invention will be explained herein relative to brooders or poult cages as a non-limiting example.
2. Description of the Prior Art
Brooders and poult cages are known in the art and a poult cage heater is described in Japanese Utility Model Registration No. 921354. In brooders known in the art, almost all of the warming apparatuses use frameworks (or frames) having large surface areas as a radiation surface. The frames are heated with a burner and radiation heat radiated from the heated frames is utilized. However, a frame has a considerable weight and therefore, it is necessary to use a brooder having a strong ceiling so as to support the heavy warming apparatus. Further, a frame has a tendency to crack by the repetition of thermal stress and shock which are caused by rapid temperature changes. Such cracking of the frame often injures poults by dropping fragments of the frame thereon. Further, if a heated frame drops on tobacco or grains, it would result in a danger of fire.
I have noted the deficiencies of the framework-type warming apparatus and have studied for a long time to develop a light weight warming apparatus which has high heating efficiency and has no risk to cause cracking. It was known prior to the present invention that a warming apparatus may have a single radiator made of perforated metal plate. However, the warming apparatus having a single radiator made of a perforated metal plate shows insufficient heating efficiency and the heating efficiency itself varies in a wide range depending upon the regulation of the fuel gas flow rate by a thermostat. The reason for the wide variation of heating efficiency would be ascribed to the fact that by the regulation of the fuel gas flow rate, the shape and size of the flame are varied and the contact of the flame with the perforated plate changes significantly. Further the regulation of the fuel gas flow rate often causes local heating of the radiator and if a small flame is used, the flame cannot contact with the perforated plate.
Prior to the study to develop the present invention, I studied how to overcome the deficiencies mentioned above concerning a warming apparatus having a single radiator made of a perforated metal plate, and found that if radiators made of perforated metal plates are disposed adjacent each other and flame is to be located between the two radiators, heating efficiency is improved and the radiators are heated substantially uniformly independent of the fuel gas flow rate. I had found that by the use of the warming apparatus having dual radiators made of perforated metal plates, fuel consumption could be saved by around 20% even in full capacity operation, and could be saved by around 50% in a low capacity operation by throttling a fuel valve when compared with conventional warming apparatuses heretofore used. Based upon the findings described above, I proposed a warming apparatus having dual radiators made of perforated metal plates (Japanese Utility Model application No. 89245/1978; Japanese Utility Model Disclosure No. 10003/1980).
I prepared 50 units of warming apparatuses in accordance with Japanese Utility Model application No. 89245/1978 and they were tested in poultry yards. Unexpectedly, the results reported by the poultry yards were unfavorable. The poultry yards reported that the warming apparatuses often exhibit backfiring. The burners used in the warming apparatuses supplied for testing were burners of conventional type used successfully for a long time in conventional frame-work type warming apparatuses without receiving reports on backfiring.